Pile raising control mechanism



July 31, 1962 K. H. GULICK PlLE RAISING CONTROL MECHANISM Filed Aug. 18, 1958 2 Sheets-Sheet 1 INVENTOR.

kE/VNETH H. auuc 37 MM u/ i j A GEN! July 31, 1962 K. GULICK PlLE RAISING CONTROL MECHANISM 2 Sheets-Sheet 2 Filed Aug. 18, 1958 INVENTOR.

KENNETH H GUUGK H AGENT United States This invention relates specifically to automatic control of pile advancing or raising mechanism of a sheet feeder for maintaining a top of a pile of sheets within predetermined high and low limits.

The principal object of this invention is to provide for raising of a pile of sheets during a multiple of sheet feeding cycles to maintain the top of the pile at an approximate predetermined level, the control of such raising being timed independently of sheet feeding speed.

Another object is to provide for adjustment of the timing of such control means to vary the amount the pile is raised, or to obtain the same amount of raising at different speeds.

More specifically, it is an object of this invention to provide for use in connection with intermittently-operated pile height detecting means, a pile advancing means having control mechanism operable independently of the sheet feeder with which it is associated and independently of continued intermittent operation of the detecting means once the control mechanism has been set in operation.

A further object is to provide that such pile height detecting means constitute a portion of a reciprocable sheet lifting sucker for separating and feeding sheets from the feeder to a sheet handling machine.

Another object is to provide for operation of said control means by an electric switch which is momentarily operated by vacuum supplied to the sheet lifting sucker for lifting sheets, such operation of the switch occurring when the sucker reaches a level at which the top of the pile is detected to be low, and raising is to be commenced.

Another object of the invention is to provide for use in connection with a sheet feeder having pile advancing means driven at a speed proportional to feeding speed and a time delay control therefor which is independent of feeding speed, an adjustment for said control for operating over different periods of time to enable raising of the pile a specified distance regardless of feeding speed.

Other objects and advantages will be apparent from the following description in which reference is had to the accompanying drawings.

According to the invention, a pile height detecting mechanism, which preferably constitutes a portion of a sheet lifting sucker, is adapted, when the pile reaches a predetermined low limit, to set in motion a time delay control mechanism for operating pile raising mechanism for a specified time period selected in accordance with the amount the pile is to be raised. The time delay period may be adjusted, and in those cases in which the pile raising speed is directly proportional to the sheet feeding speed preferably is adjusted, to obtain the proper amount of raising independently of feeding speed.

In the drawings:

FIG. 1 is a schematic side elevational view of portions of a sheet feeder illustrating a form of the pile height control means of the invention.

FIG. 2 is an enlarged view of a sheet lifting sucker which performs the pile height detecting function, including a portion of the control means.

Referring now to FIG. 1 a pile of sheets is carried on a skid 11, which in turn is supported on a pile support 12. The pile support is adapted to be raised and lowered relative to a floor 13 by cables 14 operated from a pile advancing or raising mechanism 15. The pile raising mechanism is preferably of the type dis closed and claimed in my co-pending US. application Ser. No. 553,536 filed December 16, 1955, now U.S. Patent No. 2,912,243. Briefly, this pile raising mechanism includes a drive shaft '16 from a sheet handling machine to which the sheet feeder is connected, and an electric clutch 17 which has its input element connected to the shaft 16 by means of a chain 18 and its output element connected to a worm 19 through gearing within a transmission box 20. The clutch 17 is normally disengaged but is adapted to be engaged when electrical contacts 21 are energized as will be described hereinafter. The Worm 19 drives a worm gear 22 on a shaft 23. Also mounted on the shaft 23 is a reel 24 about which the cables 14 wind and unwind to raise and lower the pile support 12. The cables 14 pass over pulleys 25 and are connected to the support.

Sheets are seized on at a time by sheet lifting suckers 26, which in the preferred form of the invention also serve to forward the sheets to pull-in wheels 27. The wheels 27 drive the sheets to a printing press, coating machine, or other sheet handling machine. The suckers 25 may be any of several different types which have a telescoping action, i.e., a reciprocating movement generally perpendicular to the top of the pile. In the form shown, the suckers are of the type shown and described in my co-pending US. application Ser. No. 755,572, filed on even date herewith, now U.S. Patent No. 2,995,- 359. Reference to FIG. 2 at this point will assist in an understanding of how this particular sucker operates. Vacuum is first applied to a chamber 29 in a cylinder 30 from a flexible hose 31. The vacuum in the chamber 29 acts on the underside of a piston 32 which is supported in its upper position in the cylinder by a compression spring 33. The piston is urged downwardly by the vacuum until a rubber suction mouth 34 engages the top of the pile 10. When this occurs, timed vacuum is applied from a pump through a hose 35 to a chamber 36 in the top of the cylinder. The suction mouth 34 is pneumatically connected to the chamber 36 by means of an opening 37 in a stem 38 interconnecting the piston 32 and the suction mouth 34. With vacuum 011 in the chamber 36 and at the suction mouth 34, the top sheet of the pile 10 is seized. Vacuum is then shut olf in the chamber 29 and the piston, stem and sucker are raised rapidly due to the action of the suction in the chamber on the top of the piston 32 combined with the lower relative pressure in the chamber 29 and the assistance of the spring 33.

Referring again to FIG. 1, when the pile of sheets 10 has been substantially depleted by the sucker 26 due to the removal of sheets, a switch 39 is actuated from one of the lifting suckers 26 and sets in operation a time delay control mechanism 40. Operation of the time delay mechanism energizes the contacts 21 to engage the clutch 17. This causes the worm 19, worm gear 22 and cables 14 to raise the pile support 12 and thus the pile 10. The amount of raising may range from a small fraction of an inch to an inch or more depending on the extent of operation of the sheet lifting suckers, their ability to separate sheets, the feeding speed, and other factors. The time delay mechanism 40 is provided with a knob 41 which carries an indicator 42 to set the amount of time such mechanism is to be maintained in operation after it is once energized by the switch 39. The switch 39 is preferably of the vacuum actuated type. One such switch is shown in detail in FIG. 2. The switch 39 comprises contacts 43 which are operated by a pin 44 connected to a diaphragm 45. When the diaphragm is in its position shown, the pin 44 maintains the contacts 43 open. However, when vacuum is supplied to a chamber 46, the diaphragm 45 is urged to the right and the pin 44 allows a resilient portion 47 of the contacts 43 to close the contacts. This sets in motion the timer 40. The timer 40 can be one which is energized but momentarily, and once energized, is maintained in operation for a selected time according to the setting of the indicator 42 with its dial 48. Once the time delay period has elapsed, and the pile has been raised to a high limit, the timer stops and resets itself automatically for subsequent operation when the switch 39 is again actuated.

Actuation of the switch 39 is accomplished as follows. When the piston 32, stem 38 and suction mouth 34 are against the top of the pile 10, a transverse opening 49 in the stem 38 will or will not connect with an annular recess 50 in a bottom end cap 51 of the cylinder 39, depending on the position of the top level of the pile L at that time. Whenever the top of the pile is between the level designated AA to B-B' the opening 49 and recess 5% will not coincide. When, however, the pile has been depleted to the point at which the lower limit designated B-B' is reached, the holes will coincide and vacuum in the opening 37 in the stem 38 will be communicated to the chamber 46 of the vacuum switch 39 through a hose 52. When this occurs, and the switch 39 is operated, the clutch will be energized to raise the pile until the top of the pile again reaches the high or A-A' limit. During the period of raising, the opening 49 may coincide with the recess 50 several times, but this will have no effect on the time delay mechanism 40 since just a single momentary impulse is necessary to start its control period. Subsequent impulses during the period serve no beneficial or harmful purpose. To release the vacuum in the chamber 46 and enable the contacts 43 to again be opened, any means may be provided to produce atmospheric pressure in the chamber. This is shown simply as a tiny port 53 in a portion of the housing of the switch 39 communicating with the chamber 46.

The distance the pile is raised is controlled by the length of time the time delay mechanism 40 remains in operation. When the drive to the pile raising mechanism is proportional to feeding speed, it can be seen that the higher the feeding speed, the less time is required to raise the pile the selected distance. The actual time required may vary considerably depending on several factors. It has been found that when using a pile raising mechanism constructed according to my previously mentioned application Ser. No. 553,536, the time delay may vary from about 9 seconds when feeding at 75 sheets per minute to approximately 4 /2 seconds when feeding 150 sheets per minute, if the distance the pile is to be raised is about three eights of an inch.

The operation of the device is as follows. When the suction mouth 34 has reached downwardly a suflicient distance to determine that the top of the pile is at its low limit, the opening 49 in the stem 38 and the recess 50 in the cap 51 coincide to produce vacuum in the chamber 46 of the switch 39 through the hose 52. This actuates the contacts 43 of the switch momentarily which in turn energize electrical apparatus in the time delay mechanism 40. Once energized, the timer runs through its pre-selected timing cycle, to cause energization of the clutch 17 through its contacts 21. This in turn causes the cables 14 to raise the pile support 12 and thus the pile 10. After the time delay period has elapsed, the timer 40 stops and resets itself for subsequent actuation. When enough sheets have been fed from the top of the pile by the sheet lifting suckers 26 to again detect that the pile has reached its low limit, the cycle is repeated.

Various modifications may be made without departing from the spirit and scope of the claims.

Having described my invention, I claim:

1. In a machine for feeding sheets from a pile to a sheet handling machine, a member reciprocable toward the pile into engagement therewith and away from the pile once for each sheet fed, a pile support, pile advancing means operably connected to said support and adapted to be intermittently operated to maintain the top of the pile within predetermined high and low limits within the reach of the member, means momentarily operable by said member when the member reaches its low limit, and time delay control means operable independently of cyclical operation of said machine for controlling operation of said pile advancing means, said control means being actuated by the means operated by said member to cause the advancing means to advance the pile when the top of the pile has been depleted to its low limit and being timed to discontinue advancing when the pile reaches its predetermined high limit.

2. Mechanism according to claim 1 including means for selectively adjusting the time delay means to operate over different time periods.

3. Mechanism according to claim 2 in which said pile advancing means includes an electric clutch having an input element driven at a speed proportional to feeding speed, and in which the time delay control means includes electrically operated switches operatively connected to said electric clutch.

4. Mechanism according to claim 1 wherein said momentarily operable means comprises a pneumatically operated electric switch for initially actuating the time delay means, and wherein said member includes valving means connected to said switch and operable by said member to actuate said switch when the member reaches the predetermined low limit of the pile.

5. In a machine for feeding sheets from a pile to a sheet handling machine, a sheet-seizing member reciprocable toward the pile into engagement therewith and away from the pile to remove the top sheet therefrom, a pile support, pile advancing means operably connected to said support and adapted to be intermittently operated to maintain the top of the pile within predetermined high and low limits within the reach of the member, means momentarily operable by said sheet-seizing member when the member reaches the low limit of the pile, and time delay control means operable independently of cyclical operation of said machine for controlling operation of said pile advancing means, said control means being actuated by the means operated by said sheet-seizing member to cause the advancing means to advance the pile when the top of the pile has been depleted to its low limit and being timed to discontinue advancing when the pile reaches its high limit.

6. Mechanism according to claim 5 wherein said sheet seizing member comprises a telescoping sucker having a cylinder with a piston reciprocable therein and a hollow stem connected to said piston and supporting a suction mouth to grip the sheets, said hollow stern having a transverse port communicating to the exterior of said stem, said momentarily operable means comprising a pneumatically actuated member, and connections from said pneumatically actuated member to said telescoping sucker whereby, upon movement of the sucker to its low position, the port in said tube communicates with said pneumatically actuated member to actuate said member by the vacuum produced to grip sheets.

7. Mechanism according to claim 6 wherein said momentarily operable means comprises a pneumatically operated electric switch for initially actuating the time-delay control means.

8. Mechanism according to claim 5 including means for selectively adjusting the time delay means to operate over different time periods.

9. Mechanism according to claim 8 in which said pile advancing means includes an electric clutch having an input element driven at a speed proportional to feeding speed of said machine, and in which the time delay control means includes electrically operated switches operatively connected to said electric clutch.

10. Mechanism according to claim 5 wherein said momentarily operable means comprises a pneumatically operated electric switch for initially actuating the time delay means and wherein said member includes valving means connected to said switch and operable by said sheet seizing member to actuate said switch when the member reaches the predetermined low limit of the pile.

11. In a machine for feeding sheets one at a time from a pile to a sheet handling machine, sheet feeding means, a pile support for said pile, pile advancing means operably connected to said support and adapted to be intermittently operated to maintain the top of the pile Within predetermined high and low limits Within the reach of the sheet feeding means, detecting means for sensing when the top of the pile reaches its low limit during the continued feeding of sheets, and time delay control means operable independently of cyclical operation of said machine for controlling operation of said pile advancing means, said control means being actuated in response to sensing by the detecting means that the pile has reached its low limit to cause the advancing means to operate for a preselected time period sutficient to advance the pile to its high limit.

12. Mechanism according to claim 11 including means for selectively adjusting the time delay control means to operate over different time periods.

References Cited in the file of this patent UNITED STATES PATENTS 2,156,648 Baker et al. May 2, 1939 2,160,491 Cernak May 30, 1939 2,530,670 Von Hofe Nov. 21, 1950 2,714,006 Layden July 26, 1955 2,746,753 Battey May 22, 1956 FOREIGN PATENTS 581,829 Great Britain Oct. 25, 1946 

